Research on High Power Density Driving Technology Based on Airborne Brushless DC Motor with Three-phase Continuous Current

Optimization and improvement methods are proposed in two aspects of control strategy and circuit design in order to meet the requirements of high power density and high efficiency of airborne and missile-home servo drive system. Aiming at the defects of the traditional "pairwise conduction" driving mode of BLDCM (BLDCM), a "three-phase current continuous" driving strategy is proposed. Based on the torque and back EMF equation, the extremum of current with minimum copper loss is resolved, and the extremum is distributed to 12 completely divided sectors. Through two-phase current closed-loop control, the three-phase current is output continuously, the non-commutation current ripple is suppressed, and the copper loss of the motor is reduced. Aiming at the optimization of power drive circuit, the high-efficiency drive technology of BLDCM based on parallel SiC MOSFET architecture is adopted, the mechanism of non-current sharing is analyzed, and the method based on independent drive is adopted to improve the parallel current sharing effect. Taking the drive system of airborne BLDCM working at the power of 25kW as the application object, the simulation and test results have shown that the combined application of the "three-phase current continuous" drive strategy and the multi-transistor parallel SiC MOSFET structure power drive circuit can effectively improve the power density of the servo drive system on airborne and missile-borne.